Course: B.Sc Botany

Semester: I

Paper: Microbiology and Phycology /BOT CC 101

Topic: Classification of Kingdoms and their criteria.

Faculty: Dr. Urvashi Sinha

E mail: urvashi_vrm@yahoo.co.in

THE CONCEPT

Carl Linnaeus introduced the rank-based system of nomenclature into biology in1735, the highest rank was given the name"kingdom”, Which forms integral partof European Botanical Research Criterion.

• In 1990, the rank of domain was introduced above kingdom.

• In biology, Kingdoms are the second highest taxonomic groups of living organisms

The hierarchy of biological classification's seven major

taxonomic ranks.

Historical development

• Aristotle (384-322 BC) Scientific classification of living beings was first doneby him. He used morphological characters as the basis of classification. Heclassified the living beings into plants and animals.Aristotle’s classificationwas largely influenced by Ancient Indian, Morphological & Biologicalevidences, illustrated in Ancient Indian History which was later concludedin the “Vedic Age” by findings based on Indus Valley Civilization. Hefurther classified the plant into trees, shrubs and herbs. He furtherclassified the animals on the basis of presence of absence of redbloodCells and for certain Species of Animals, White Blood cells as well, whichforms Antibodies!.

• Linnaeus (1735) for the first time established two kingdoms of organisms inhis classification system: Plantae (the plant kingdom) and Animalia (theanimalkingdom).

• Since then, scientists have repeatedly revised the Linnaean system. Theyhave added several new kingdoms and other taxa. These changes werenecessary as scientists learned more about life onEarth

Kingdom Plantae

• single-celled organisms, some of which make their own food. They were classified as plants.

Kingdom Animalia

• single-celled organisms that can move on their own. They were classified as animals, which are organisms that have independent movement.

Linnaeus (1735) created his taxonomy

Two kingdom system

The German biologist Earnst Haeckel (1866):Three kingdom system

Kingdom Protista

Kingdom Plantae

Kingdom Animalia

Single-celled organisms

Didn’t seem tofit in either the plant or the animalkingdom

Included bothbacteria and protozoa

Multicelled-celled organisms,some of which make their ownfood.

Included all chlorophyllcontaining organisms

Multicelled-celled organismsthat have independent movement.

Included all vertebrates, arthropods and human

Diversity in Protistae

When you compare the three cells i.e bacteria, the protozoa and themulticelled plants and the animal, what differences do yousee?

The major difference is that, unlike the protozoan and animal cells:

The bacterial cell does not contain a nucleussurrounded by a nuclear membrane. Instead, its DNA is found in the cytoplasm of thecell.

Organelles in the bacterial cell also lack surrounding

membranes.

Unicellular organisms.

Organelles lack membrane.•

An organism whosecellslack nuclei and the

Prokaryote

Unicellular and multicellularboth.

Membrane boundcellOrganelles.

An organism whosecellshave nuclei.

Eukaryote

In the 1920s, microbiologist Edouard Chatton gave

the term Prokaryote and Eukaryote Cells

Over the next several decades, scientists learned more about thetremendous number and diversity of bacteria. They started to see a

need for a separate bacteria kingdom

Proposed by Herbert Copeland (1956): Four Kingdom system

Kingdom Monera Kingdom Protista Kingdom Plantae Kingdom Animalia

Elevating the Protist classes of bacteria (Monera)and blue-green algae.

Prokaryotes,Unicellular organisms

Eukaryotes

Unicellular,organisms

Slimemoulds,Protozoans

Eukryoticchlorophyllcontainingorganisms

Includes Algae,Bryophytes, Pteridophytes,Gymnospermsand Angiosperms

Eukaryotic multicelled arthopods, vertebrates and human.

1 Monera

1. Protista

2. Fungi

3. Plantae

4. Animalia

R.H. Whittaker (1969), an American Taxonomist, classified all organisms into five kingdoms: Five Kingdom System of Classification

5. Complexity of cell structure

2. The mode of nutrition

3. Life style (ecological role)

4. Phylogenetic relationship.

Criteria used for classification by Whittaker for 5 kingdom classification system.

1. Complexity of body organization

Kingdom I: Monera

Prokaryotes, unicellular,

Bacteria occur everywhere and they are microscopic

innature.

They possess cell wall and are prokaryotic. The cell wall is formedof

amino acids and polysaccharides.

Bacteria can be heterotrophic andautotrophic.

The heterotrophic bacteria can be parasitic orsaprophytic.

The autotrophic bacteria can be chemosynthetic orphotosynthetic.Bacteria can be classified into four types based on their shape:

Coccus (pl.: cocci)- These are spherical in shape. Bacillus (pl.: bacilli) – These are Rod-shaped, Vibrium (pl.: vibrio) –These Comma-shapedbacteria

Spirillum (pl.: spirilla)- These are Spiral shaped bacteria

Monera has since been divided into Archaebacteria and Eubacteria

Kingdom Monera

Bacteria, Cyanobacteria or Blue green algae

Kingdom Protista

Unicellular and eukaryotes. Have cilia or flagella for mobility. Sexual reproduction by cell fusion and zygote formation. Categorized into

subsequent groups:Chrysophytes: The golden algae (desmids) and diatoms are fall under thisgroup. They are found in marine and freshwater habitats.Diano flagellates: They are usually photosynthetic and marine. The colour they appear is dependent on the key pigments in their cells; they appear red, blue, brown, green or yellow.Euglenoids: Most of them live in freshwater habitation in motionless water. Cell wall is absent in them and instead there is a protein rich layer; called pellicle.Slime Moulds: These are saprophytic. They body moves along putrefying leaves and twigs and nourishes itself on organic material. Under favorablesurroundings, they form an accumulation called plasmodium.Protozoans: They are heterotrophs and survive either as parasites orpredators

Kingdom Protista

Protozoans, Phytoplanktons and

Zooplanktons

Kingdom Fungi

The fungi are filamentous; excluding yeast (single celled).

Their thallus comprises of slender, long thread-like constructions;

called hyphae

The cell wall of fungi is composed ofpolysaccharides and chitin.

Most of the fungi are saprophytes and are heterotrophic.

Unicellular Yeast, Molds and Mushrooms

Kingdom Fungi

Kingdom Plantae

Eukaryotes which have chloroplast.

Most of them are autotrophic in nature, but someare

heterotrophic as well.

The Cell wall mainly comprises ofcellulose.

Plants have two distinctive phases in their life cycle.

These phases alternate with each other. The diploid

saprophytic and the haploid gametophytic phase.

Algae, Bryaophytes, Ferns , Gymnosperms Muticelled Eukaryotes

Kingdom Plantae

Kingdom Animalaia

All multicellular eukaryotes which are heterotrophs and lack cell wall.

Their mode of nutrition is holozoic.

Sexual reproduction is by copulation of male and female which is followed by embryological development.

Sponges, Invertebrates, Vertebrates and

Multicelled eukaryotes

Kingdom Animalia

Sl.No.Kingdom

IKingdom

IIKingdom

IIIKingdom

IVKingdom

V

Characters Monera Protista Fungi Plantae Animalia

Complexity of cell structure

Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote

Complexity of cell organization

Unicellular Unicellular Unicellular And Multicelled

Multicelled Multicelled

Mode ofnutrition

Absorptive

/Photosynt

hetic

Absorptive

/Photosynt

hetic

Heterotrop hic, Saprobic

Auto-

trophic

Hetero-

trophic

Movement By flagella By flagella

Celia

Non-motile Non-motile Highly

motile

Mode ofReproduction

Asexual Both asexual, sexual

Both asexual,sexual

Both asexual,sexual

Both asexual, sexual